Flushing oils



Patented Aug. 8, 1944 FLUsnmGoILS Marcellus T. Flaxman, Inglewood, Caliiassignor to Union Oil Company of California, Los Angeles, Call! acorporation of California No Drawing. Application January 14, 1941,

Serial No. 374,369

22 Claims.

This invention relates primarily to oils for flushing lntemal combustionengines by use of the same in the crank case for a period of time inplace of the usual lubricating oil.

The object of the invention is to furnish oil having lubricatingproperties and of such constitution that it will act to remove depositsfrom the cylinder walls, contiguous piston walls and the piston ringsand grooves, as well as from the walls of the crank case, the insidewalls of the pistons, the crankshaft and the oil pump screen.

The present invention resides largely in, a

mineral oil having at least some lubricating properties and containing alarge quantity of water held in solution by means of agents possessingwater-retaining and common solvent properties.

I have found that large quantities of water can be retained inlubricating oils by means of oilsoluble petroleum sulfonates, and thatat the same time freely fluid dispersions or solutions are producedhaving. no emulsion orgrease-like properties, which may be entirelyclear. The resultant soap and water composition will remove depositsfrom the walls of the crank case, pistons and cylinders and from pistonrings and piston grooves when used in the place of lubricating oil inthe crank case of an internal combustion engine for an appreciablelength of time, such as one hour.

The detergent action possibly is the efiect, or is in part the effect,of particular colloidal conditions of hydrated soaps produced withappropriate water contents but I do not wish to be bound in all eventsby such theory.

According to one preferred form of the invention, I employ in a minerallubricating oil, preferably a light mineral lubricating oil, a quantityof the sodium or potassium salt or soap of oil-soluble sulfonic acidsfrom the treatment of petroleum oil-soluble sulionic acids obtained inthe treat-- mentor various mineral lubricating oils and the likewithsulfuric acid. One such is known as "Petronate produced by Sonneborn andSons of New York city. Corresponding synthetic compounds are alsosometimes available on the market and may be used. Any minerallubricating oil, especially the light lubricating oils, may be employedas the oil constituent. A desirable oil is a low viscosity acid-treatednaphthenic base oil in the SAE 5 range which has a viscosity of aroundseconds Saybolt Universal at 100 F. Lighter oils having lubricatingqualities such as the socalled spray oils can be employed, and alsoheavier oils such as those of SAE 20 and 30 grades- The oils may be ofeither parafiinic or naphthenic type. In some instances it might even beappropriate to substitute kerosene. In general, the greater theproportion of sulfonate, the greater the proportion of water which canbe retained. Where water contents are much above 35% or 40%, the oils donot appear to be efiective until the water has boiled oil to reduce itto the 35% to 40% range. The effective water range seems to be betweenabout 5% and about 35%, at least with 10% to 15% sulfonate. Ordinarily10% sulfonate and 20% to 25% water are used. As specific examples, wehave prepared compositions approximatelyas follows (proportions being inIn the above table, it will be noted that where the proportion of wateris small with respect to the sulfonate, that is where the water is abouttwice that of the sulfonate, no common solvent is used; that is found inExamples I, II and III. However, as shown in the other examples, where afew percent of the common solvent is employed, the water content withrespect to any given proportion of sulfonate is subject to considerableincrease. The last example also shows that, at least in some cases, thewater content may be further increased with an increase in the commonsolvent. All examples show that as the sulfonate is increased the watercontent may be increased. Of course, the suifonate content may beincreased without increasing the water content. A typical practicalcomposition for commercial use is that shown in Example V.

Further, with respect to these examples, while for most practicalpurposes it is probably D erable to employ the common solvent,nevertheless good results are obtained at normal temperatures or higherwithout the common solvent so long as the proportion of water does notexceed that which may enter into proper solution. In .the case ofExamples I, II and III, clear solutions may be readily obtained,although upon standing at temperatures appreciably below roomtemperature there may be a tendency to cloud, and, especially ii thewater content is substantially increased without corresponding increasein sulionate, there may be a tendency toward some water separation instorage. However, this need not be necessarily objectionable for usewhen the material is stocked in 5 or 6 quart cans whose contents are tobe poured directly into the engine being flushed. In such instancescloudiness is no objection and the heat oi the engine soon brings aboutadequate solution. However, this condition may be avoided by employingappropriate amounts of common solvent, which as indicated may varybetween about 2% or 3% and 10%. The examples also indicate that thereordinarily is a practical water limit for each percentage of sulfonateor oi sulfonate and common solvent. Thus, for about oi sulfonate thepractical water limit would be about 30% without common solvent, andabout 40% with about 4% or 5% of common solvent. The sulfonate could beincreased to although without particular additional advantage.

In order to increase the detergency oi the composition, aromaticsolvents, straight run naphthas and other petroleum thinners and thelike may be added to replace a portion oi the lubricating 011. Forexample, 15% or 20% of an aromatic solvent could be used in any of theabove examples in place of a corresponding proportion of the mineraloil. Such solvents, or thinners will also have some common solventeil'ect, and would exert such effect in Examples 1, II and III.

In general, proportions are not critical, although, as has beenindicated, there are reasonable practical limits, and as water contentsin crease especially above those given, greater caution is required incompounding. For example, in most cases where the water content is toexceed about such precautionary measures are found in diluting thesulfonate with approximately an equal quantity of oil, mixing the watertherewith, employing agitation and ordinarily also warming to 100 F. orup to perhaps 150 F. until a clear solution is obtained, thereuponadding the remainder of the oil, the common solvent when used beingadded either before or after the addition of the remainder of the oil orwith said remainder of the oil. These measures are easily followed andavoid tendencies to maintain a permanent cloud. Of course, in some ofthese blending operations there is a. temporary clouding whichdisappears upon agitation or warming or standing as the case may be, andwhen a cloud tends to persist, ordinarily it may be overcome by theaddition of further amounts of common solvent, except that too muchcommon solvent after the clear stage has been reached will sometimescause a cloudy condition which may be diiflcult to remove withoutfurther increase in sulfonate.

Where the compounding procedures indicated are not followed, but adifierent order of addition is employed, it may be difllcult and attimes al most impossible to remove completely the cloudy street, butthis. does not appear to from the useiulness oi the product as aflushing oil.

It will be noted that in the examples given the mineral oil is anaphthenic base 011. Where a paramnic mineral oil is employed, it maysometimes be desirable to lower somewhat the common solvent in thoseinstances where a common solvent is required to clear the solution, e.g. 1% to 3% less.

As to the common solvent in general, 10% appears to be the maximum thatwill produce any desirable eiIect in any commercial composition. Again,since 40% (or possibly 45%) of water seems to be the absolute upperlimit of the water content with which the flushing oil is eiiective,there'is no significance in enlarging the proportion of water nor inusing the larger proportions oi the common solvent in order to clear asolution containing such larger water content. Thus, while it has beenfound possible by following the preferred procedure above indicated toplace 65 of water into solution in the naphthenic base oil with about7.5% of sulfonate and about 4% of the ethylene glycol monobutyl ethermentioned, there is often a tendency for a cloud to develop, and thereappears to be no practical advantage in trying to produce such aproduct. In general, the avoidance of cloud is more a function of theoil-sulfonate ratio with respect to the water content than oi commonsolvent with respect to water content at ordinary temperature.

With respect to the use of a common solvent of the ether type mentioned,while it has been indicated that it may be omitted in some imstances,nevertheless it is preferred to use such a common solvent in allinstances because the solvent acts to change the colloidal properties ofthe sulfonate solution and improve not only the clarity of the productbut also the eiliciency thereof. This efllciency is improved by reason01' the detergent properties possessed by the common solvent itself, andapparently also by reason to hydrate the soap, and that so longas'proper hydration exists the required efiectiveness exists.

When too much water is present this colloidal state seems to have beenaffected, and when the water is boiled out the necessary colloidal stateagain is lost.

In blending, where 15% of sulfonate is used. with about 5% or 6% of theethylene glycol monobutyl ether, when the water is poured into the oilsolution the water will disperse without clouding, up to the limit, ofwater which will otherwise be retained; whereas if only 10% of thesulfonate is present in the oil into which the water is beingintroduced, there will be a slight clouding as the water is commingledbut this clouding will clear up on brief standing. The curverepresenting the transition from a clear product to a substantiallymilky or cloudy product shows that, with a naphthenic base oil, about 5%or 6% sodium sulfonate is the minimum to retain about 10% water; thatabout 10% of sodium sulfonate is the approximate minimum to retain 30%to 35% of water, and that the curve then flattens out so that, so far asthe question of permanent clear solution is concerned, only 4% or 5%additional sodium sulfonate is essential to retain any larger proportionof water. With a paraflinic oil, the sulfonate should be 2% or 3%higher. Of course,.

as previously indicated, an appreciable amount of common solvent isusually necessary to insure a clear solution of the oil, water andsulfonate. Under these conditions, about 35% of water is the approximateupper limit when only of the sulfonate is used, but when as much as ofthe sulfonate is used there is apparently no upper limit to the watercontent, although more than about 35% to 40% of water (as aboveindicated) usually produces no desirable eifect until the excess waterboils off. Similarly, the soap may be increased, for example to butwithout any great significance. Apparently, the desideratum ismaintaining the soap (sulionate) in hydrated form. Thus, increase insoap permits increase in water to 50% or more, but an effectivecomposition is limited as indicated to around water. Also, a paraifinicoil ordinarily requires use of more sulfonate, and less common solvent,than is permitted with a naphthenic oil, the tolerance of paraflinicoils for the common solvent apparently being less than that ofnaphthentic oils.

In employing the present product, the used lubricating oil is drainedout of the crank case, the crank case is filled to the usual level withthe present flushing oil, and the engine is then run atidling speed foran appreciable length of time, e. g. one hour. For such an operation, itis important that the crankcase temperature become somewhat elevated, asbyretarding cooling. Preferably a range of 180 F. to 190 F. is employedbecause activity is low below 180 F. and the water is driven off toorapidly above 190 F. Under these conditions the soap and water, or

perhaps more properly the hydrated soap, be-

comes very active, and especially in the case of a light oil. The wholesolution, especially where common solvent is present, penetrates readilyalong the piston walls to the rings and ring grooves. Here the solutionhas apparently a solvent efiect upon accumulations containing the usualresinous and varnish-like deposits, and results in the washing away ofdeposits not dissolved, e. g. carbon particles.

Apparently the-oil is effective until all or nearly all of the water hasbeen boiled out, and perhaps for somewhat longer period due to thepresence of the sulfonate or the common solvent when used. Asixty-minute flushing period produces very beneficial effects. Sincetheoil is to be a sufiiciently good lubricating oil for whatever periodof time the engine is to be cleansed, it may be so operated for longeror shorter periods. However, if the oil from which the product isprepared is a suitable quality lubricating oil an automobile engine maybe run while the car is in service for a time adequate to insurethorough flushing. For example, 100 miles at normal crankcasetemperatures will suffice. Lighter oils are required where good flushingof the piston rings and grooves is required. Otherwise, heavier oils, e.g. S. A. E. 30, may be used whereby only the crankcase and pan are to beflushed and leaned. It is also possible to use the old oil already-inthe crankcase, without draining, by introducing the mentioned additivesinto the crankcase and forming the solution or blend in situ. Duringtreatment of the engine the flushing oil becomes quite black and dirty,and is removed at the end of the flushing period. To some extent oilfilters are also cleaned, solid materials which are not soluble in theflushing oil, e. g. carbon particles, being carried oil" in suspension.

With respect to substitutes, no thoroughly satisfactory commercialcommon solvent has yet been found and tested to replace. the ethyleneglycol mono-butyl ether mentioned, when naphthenic base oils are used,although the expensive phenyl Cellosolve" (phenyl ether of ethyleneglycol) is good, and doubtless there are known materials of naturesomewhat kindred to these which would be suitable equivalents. However,where more paraflinic oils, i. e. oils of higher viscosity index areused, not only is less common solvent usually required, say 1% to 3%less, but the range of common solvents increases; those of the type ofdibutanol, butyl carbitol" (butyl ether of diethylene glycol) andpropylene glycol have been used. Dibutanol is stated by itsmanufacturers, Carbide and Carbon Chemicals Corporation, in their 1939booklet entitled Fine Chemicals, to have the following formula:

This is a glycol type derivative. As a substitute for the sodium orpotassium sulfonates, other sulfonates having adequate detergentproperties which are adequately oil-soluble and will not themselves tendto leave deposits during the flushing operation, may be used. Examplesof these are the triethanolamine sulfonates, and ammonium sulfonates.However, other oil-soluuble detergent sulfonates such as the alkalineearth metal sulfonates may be used. Thus, calcium, barium, strontium andmagnesium sulfonates are indicated as having at least appreciablevalue,and also those of metals such as zinc, aluminum, chromium, iron, tin,copper, cadmium and the like.

So far as variations in percentages are concerned, these have beenindicated. However, as to butyl Cellosolve, the percentage variationswill be between about 2% and 10%. The common solvent may be entirelyomitted as has been indicated where only temperatures of about 75 F. orhigher are to be encountered, or where clouding or settling is noobjection. Possibly water down to 2% or 3% is beneficial.

This oil product may be used for other appropriate purposes, for exampleas a cutting oil especially where 30% or larger proportions of water arepresent, as may be readily attained to almost any limit when about 20%of sulfonater or possibly a little more in some instances, is used.

I claim:

l. A flushing oil comprising a major proportion of mineral lubricatingoil fraction, between about 10% and 35% of water, and between about 5%and 15% of an alkali metal petroleum sulfonate.

2. A flushing oil for internal combustion engines comprising at leastabout 33% of light lubricating oil, between about 10% and 45% of water,and between about 10% and 15% of oilsoluble petroleum sulfonate.

3. A flushing oil for internal combustion engines comprising at leastabout 40% of lubricating oil, between about 10% and 35% of water, andbetween about 10% and 15% of sodium sulfonate derived from petroleum.

4. A flushing oil according to claim 1 containing in the order of 2% to10% of common solvent.

5. A flushing oil according to claim 2. containing in the order of 2% to10% of ethylene glycol monobutyl ether.

6. A flushing oil composition comprising mineral lubricating oil a majorproportion, between about 10% and 35% of water and in the order of about10% of anon-soluble metal sulfonate derived from petroleum.

7. A flushing oil composition according to claim 6 containing in theorder of 2% to 10% of a common solvent.

8. A ilushingoil for internal combustion engines containing a majorproportion 01 light mineral lubricating oil in the S. A. E. to range,about to water, and about 10% of oil-soluble sulfonate derived frompetroleum.

9. A flushing lubricant comprising in the order of 60% to 65% of lightlubricating oil, in the order of 25% to 20% of water, in the order of 5%of a common solvent, and in the order of 10% oi oil-soluble sodiumsulfonate derived from the treatment of petroleum fractions withsulfuric acid.

10. A flushing oil for internal combustion engines containing at leastabout 33% lubricating oil, between about 5% and about 20% of oil-solublepetroleum sulfonate, and more than about 10% of water.

11. A flushing oil according to claim 10 containing between about 2% andabout 10% of a common solvent.

12. A flushing 011 according to claim 10 containing between about 2% andabout 10% of a common solvent of theclass consisting oi! ethylene glycolmonobutyl ether, phenyl ether of ethylene glycol, dibutanol, and butylether of diethylene glycol.

13. A flushing oil according to claim 10 containing in the order of 2%to 10% of ethylene glycol monobutyl ether.

14. A method for operating internal combustion engines comprisingoperating such an engine with its istons, cylinder walls, connectingrods, crank shaftsand bearings in contact with a composition comprisingat least about 33% of lubrieating oil, between about 10% and 50% ofwater and between about 5% and 20% of oil-soluble petroleum sulionate,whereby deposits in the ensine are removed from the mentioned engineparts.

15. A method according to claim 14 wherein the composition contains inthe order of 2% to 10% of common solvent.

16. A flushing oil for internal combustion engines containing at leastabout one-third mineral lubricating oil, between about 5% and 20% ofoilsoluble petroleum sulfonate, and in the order of 20% to 40% of water.

17. A flushing 011 according to claim 16 containing between about 2% andabout 10% of a common solvent.

18. A flushing 011 according to claim 10 containing in the order of 2%to 10% of common solvent containing a glycol grouping.

19. A flushing 011 according to claim 10 containing in the order of 5%of ethylene glycol monobutyl ether.

20. A flushing oil according to claim 15 containing a small proportionin the order of 5% of a common solvent.

21. A flushing oil comprising a major proportion of mineral lubricatingoil fraction containing between about 5% and about 20% of oilsolublesulfonate and more than 10% water, the composition being relatively freefrom aromatic petroleum fractions.

22. A flushing oil for internal combustion engines containing at leastone-third mineral lubricating oil, between about 5% and about 20% 01'oil-soluble petroleum sulfonate, and more than 10% water, thecomposition being relati 1y free from aromatic petroleum fractions.

MARCEILUS T. FLAXMAN.

